Detection of unwanted communications, compromised data, and malware has been an increasing concern as networked communication continues to grow at tremendous rates. With the growth of communication networks such as the Internet, the increasing amount of data interchange, and more recently the growth of cloud computing, the vulnerability of computers and servers through networked communication has become an increasingly significant issue. In particular, electronic mail communication has been plagued by high volumes of junk mail (e.g., spam and other unsolicited communications) as well as malicious communications (malware, phishing attempts, and other maliciously crafted electronic content). Some filtering solutions have been developed to combat these unwanted communications. For example, service providers have used heuristic detection and filtering to identify and quarantine unwanted communications. These heuristic approaches may rely on granting to a service provider access to messaging content to perform the filtering. While a user may employ encryption or other security measures to protect messages in transit, the user is not provided privacy from the service provider because the service provider requires access to the original message.